A new route to Phenylacetic Acid from Styrene

Elementary · Mon May 16, 2005 6:40 pm

1. Permanganate Oxidation of Styrene to Benzoylformic Acid (Phenylglyoxylic acid)

http://216.239.39.104/translate_c?hl=en&sl=zh-CN&u=http://hxtb.icas.ac.cn/col/1999/c99025.htm&prev=/search%3Fq%3Dpermanganate%2Boxidation%2Bof%2Bstyrene%26start%3D100%26hl%3Den%26lr%3D%26sa%3DN

See also patent JP1172360 (PRODUCTION OF BENZOYLFORMIC ACID)

Abstract of JP1172360

PURPOSE:To economically obtain the title compound which is a optically active R-(-)-mandelic acid production raw material of synthetic intermediate for antibiotic, etc., without by-product, by adding emulsified styrene to an electrolytically regenerated permanganic acid alkali solution inexpensively available and oxidizing the styrene. CONSTITUTION:Oxidation reaction is carried out by adding an emulsified suspension of styrene to an electrolytically regenerated permanganic acid alkali solution, preferably sodium permanganate to provide the aimed compound. Method such as supersonic treatment, mechanical stirring by emulsifier is used as a method for emulsifying styrene into water. Regenerated sodium permanganate solution is preferably properly stirred. Furthermore, a method pouring regenerated sodium permanganate into emulsion of styrene little by little is undesirable. Electrolytically regenerated sodium permanganate solution is obtained by subjecting manganese dioxide to electrolytic regeneration with sodium hydroxide.

2. Reduction of benzoylformic acid with hydriodic acid and phosphorus to produce phenylacetic acid.

Chem. (2) 1, 443 (1865); Ber. 14, 239 (1881).

Elementary · Tue May 17, 2005 2:41 pm

Benzoylformic acid can also be prepared by the oxidation of acetophenone with potassium permanganate in alkaline solution. Claus and Neukranz, J. prakt. Chem. (2) 44, 80 (1891).

Acetophenone can be prepared by pyrolysis of Calcium Benzoate and Calcium Acetate.

lurker4711 · Fri Jun 10, 2005 6:42 pm

This works too says an japanese article:
Chlorination of styrene and treatment of the procut with KOH in alcohol (or sodium ethoxide) yields PAA in 50%+ yields.

The article calls for chlorination at 110°C with dibenzoylperoxide.

Well when you add dibenzoylperoxide to styrene and heat it you get polystyrene.
The reaction must probably be done 2-step.
First monochlorination of styrene in the cold by just venting chlorine into sytrene.
Heating up, chlorinate and the activator added in small portions.
Maybe even UV would do the trick?

Literature tells that monochlorination will proceed easily.
Heating styrene with any activator present WILL end in solid plastic.

Richy · Sat Jun 11, 2005 1:11 pm

How about heating with a hypochlorite salt, as one might perform to obtain chlorinated toluene derivatives?

lurker4711 · Sat Jun 11, 2005 4:12 pm

This might work, but would for sure require large amounts of an inert co-solvent as the volume of the hypochlorite needed would exceed the volume of styrene (complete triple chlorination is whats called for). And this would be a mess and pretty dangerous.

Co-solvent? Perchlorethylene perhaps?

Vitus · Psychoscientist

More refs:

styrene -> phenylglyoxylic acid using alkaline KMnO4:

JACS 61 (1939) p 2979

acetophenone -> phenylglyoxylic acid,

using alkaline KMnO4:

Monatsh. Chem. 11 (1890) p 248
J. Prakt. Chem. (2) 44 (1891) p 80
Proc. Roy. Soc. London A 165 (1938) 439
Chem. Zentralbl. 110 I (1939) 911

using SeO2 in pyridine:

Just. Lieb. Ann. Chem. 613 (1958) p 153, 155, 162

phenylglyoxylic acid -> phenylacetic acid using hydrazine hydrate and KOH:

Oest. Chemiker-Ztg. 51 (1950) p 77

Polverone · Sun Jun 12, 2005 5:51 am

Elementary · Sun Jun 12, 2005 6:03 pm

I thought chlorination of styrene and then treatment with alkali would give you an epoxide, rearangement of the styrene epoxide would give you phenylacetaldehyde. You would then need to oxidize the phenylacetaldehyde to phenylacetic acid.

If the benzoylformic acid could be reduced to phenylacetic acid with sodium borohydride or a dissolving metal type reduction this would make it nice and OTC (for me at least).

Vitus · Psychoscientist

Polverone:

I'm afraid I don't have access to this journal (Österreichische Chemiker-Zeitung), I've obtained the information above from Beilstein.